There are many examples of a need to operate a radio receiver and transmitter in close proximity. Often the isolation between antennas cannot be provided by passive means such as physical separation or by antenna directivity. It is known in the art to improve isolation by the use of an adaptive canceller. The present invention deals with means for extending the usefulness of adaptive cancellers over a wide band of frequencies.
It is often desirable to provide a canceller capable of adapting to several narrow frequency bands independently resulting in wide band coverage. For example, when a surveillance receiver and a jammer are operated on a small aircraft, the jammer may be switched rapidly over a wide band of frequencies including the coverage band of the receiver. The canceller adapted to one such frequency might have to readapt when the jammer jumps to another frequency.